echarts-pie-roundcap

Add roundCap option to echarts serie Pie setting

#Example：
option = {
    tooltip: {
        trigger: 'item',
        formatter: '{a} <br/>{b}: {c} ({d}%)'
    },
    legend: {
        orient: 'vertical',
        left: 10,
        data: ['直接访问', '邮件营销'
        , '联盟广告', '视频广告', '搜索引擎'
        ]
    },
    series: [
        {
            name: '访问来源',
            type: 'pie',
            radius: ['50%', '70%'],
            avoidLabelOverlap: false,
            label: {
                show: false,
                position: 'center'
            },
            emphasis: {
                label: {
                    show: true,
                    fontSize: '30',
                    fontWeight: 'bold'
                }
            },
            labelLine: {
                show: false
            },
            data: [
                {value: 335, name: '直接访问'},
                {value: 310, name: '邮件营销'}
                ,
                {value: 234, name: '联盟广告'},
                {value: 135, name: '视频广告'},
                {value: 500, name: '搜索引擎'}
            ],  
            roundCap:2// Optional Number：1 or 2，there are two modes of roundCap
        }
    ]
};